As much as I like SF, this has always been my complaint with time travel stories. In order to fix an exit point, you have to know not only your absolute position in the universe (by finding one unmoving reference point in spacetime - good luck), but you also have to know every force that affects the position of everything, basically negating the need for any info gathering trips.

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That would be a fine solution, assuming that you have a way to track the receiver through spacetime, some unique transtemporal carrier wave to home in on. Otherwise the receiver is just another bullseye for a blind sniper.
Hey, do you mind if I use this idea for a story?

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